1. Field of the Invention
The present invention relates generally to improvements in automotive engine speed control devices and, more particularly but not by way of limitation, to improvements in devices for controlling the speed of operation of drag racer engines.
2. Brief Description of the Prior Art
In the sport of drag racing, the focus is on the time required for a racing car to cover a relatively short distance from a standing start and a race will generally last for a time period of only about ten seconds. Moreover, winning and losing times in such a race will often be separated by only a few hundredths of a second.
This nature of a drag race places a premium on both the reliability of the engine of a racing car and the consistency of operation of the engine from one race to the next. For example, small differences in the ignition of different cylinders in the engine of a drag racer, differences that would go unnoticed in the family automobile, can easily lead to a loss of consistency in the time required to cover a drag race course and make the difference between a racer winning and losing races. In particular, timing of events occurring both in an engine and during a race plays a crucial role in the success of a racing car.
To meet the demands placed on drag racers, inventors have come up with a variety of devices aimed at improving the reliability and consistency of operation of drag racing car engines. One such device, which has proven to be very successful, is the multispark discharge system developed by Automatic Controls Corporation of El Paso, Tex. and disclosed in U.S. Pat. Nos. 3,926,165 and 4,131,100. This system provides a series of sparks to each cylinder during a time period in each cycle of operation of the engine to insure ignition and both the starting point and duration of the time are carefully controlled. Moreover, the system has an engine speed limiting control feature permitting a maximum engine speed to be selected by choice of a resistor that is plugged into the case of the device. Thus, the device provides a means for setting a desired engine speed during a drag race and insuring that the engine will operate in an efficient and consistent manner during a race.
Other attempts to improve the performance of a drag racing car engine have been of lesser success. In particular, devices that have been utilized for "scrubbing off"; i.e., reducing, speed in a race in which the object is to cover a fixed distance in a preselected time with disqualification of any car which covers the course in less than the prescribed time. The cars used in such races are capable of covering the distance in less than the prescribed time and are commonly run at full throttle during the early part of the race and throttled back near the end of the race. An early device used to carry out this race format comprised a switch that closed when the driver shifted from low to drive to activate a solenoid that introduced air into the cylinders of the engine. As a result, the racing car would quickly attain a high speed and then cruise to the end of the race. However, the device proved to be unsuccessful because of inconsistencies in shifting time.
More recently, a device has been developed for scrubbing off speed during a selectable interval in a race. In this device, settable timers are used to select the start and duration of the interval and circuitry is provided to actuate a solenoid connected to a mechanical throttle stop on the engine during the interval. While this device has had some success, the success is limited by expense and reliability problems that often accompany mechanical control devices. Thus, the primary contribution this device has made to the art lies only in the stratagem it employs in the conduct of a race; that is, the scrubbing off of speed during a short time interval in the race with open throttle operation to either side of the interval.